doc:it_IT: translations for documents in process/

Translated documents:
- stable-kernel-rules.rst
- deprecated.rst
- kernel-enforcement-statement.rst
- license-rules.rst

Added document to have valid links
- netdev-FAQ.rst

Modifications to main documentation
- add label in deprecated.rst

Signed-off-by: Federico Vaga <federico.vaga@vaga.pv.it>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>